HVAC Journeyman Practice Exam

How should leaks in gas piping be located?

1. With a sniffer

2. With a presto-lite flame

3. With a noncorrosive leak-detecting fluid

4. By increasing air pressure during a test

The correct answer is: With a noncorrosive leak-detecting fluid

Using noncorrosive leak-detecting fluid is the best method for locating leaks in gas piping because it provides a visible indication of a leak when applied to the joints and connections. These leak-detecting fluids usually create bubbles when they come into contact with escaping gas, making it straightforward and effective for determining the exact location of a leak. This method is safe for gas piping systems because noncorrosive fluids do not damage the piping materials and are specifically designed for this purpose. In contrast, other methods may not be as safe or effective. For example, using a sniffer, which is a device to detect gas in the air, may not accurately indicate the leak's location; it can identify the presence of gas but may not provide a definitive indication of where exactly the gas is leaking from. The option involving a presto-lite flame, typically used in specific applications for ignition testing, poses a significant safety hazard and is generally not advisable for leak detection due to the combustible nature of gas. Increasing air pressure during a test can help identify weaknesses in the system but does not directly facilitate leak detection in the same visible manner as applying a leak-detecting fluid would. Thus, the most reliable and safe method is to utilize a noncorros